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Main Idea and Its Support is a free printable Grade 4 English worksheet on working out a main idea from the details that support it, aligned to Common Core standard RI.4.2. It prints 8 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two students in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 21 of 25 · the same problems every time you open this link.

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Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Main Idea and Its Support

RI.4.2

NameDate

Circle the right answer.

1.A paragraph says: beavers fell trees with their teeth; they build dams of sticks and mud; their ponds give homes to fish and birds. What is its main idea?
  • A.Beavers change the places where they live.
  • B.Fish live in ponds.
  • C.Beavers have sharp teeth.
2.A paragraph says: honeybees carry pollen from flower to flower; without them many fruits would not grow; farmers rent hives for their orchards. What is its main idea?
  • A.Farmers keep hives.
  • B.Bees are important for growing food.
  • C.Flowers have pollen.
3.A paragraph says: trains ran to schedules across the country; each town had kept its own time; the railways needed one time everywhere. What is its main idea?
  • A.Towns had clocks.
  • B.The railways led to one time for the whole country.
  • C.Trains were often late.
4.A paragraph says: earthworms tunnel through soil and let air in; they drag dead leaves underground; their waste makes the soil richer. What is its main idea?
  • A.Earthworms help keep soil healthy.
  • B.Leaves fall in the fall.
  • C.Earthworms live underground.
5.A paragraph says: some volcanoes pour out rivers of lava; others explode in clouds of ash; some have been quiet for thousands of years. What is its main idea?
  • A.Lava is hot.
  • B.Volcanoes behave in different ways.
  • C.Ash is gray.
6.A paragraph says: Roman roads ran straight for miles; they were laid in layers so water drained away; some are still used today. What is its main idea?
  • A.Romans liked straight lines.
  • B.Roman roads were built to last.
  • C.Water drains away.
7.A paragraph says: coral reefs cover a tiny part of the sea floor; a quarter of all sea creatures live on them; many fish lay their eggs there. What is its main idea?
  • A.Coral reefs are very small.
  • B.Fish lay eggs.
  • C.Coral reefs are home to a great deal of sea life.
8.A paragraph says: lighthouses warn ships away from rocks; each one flashes its own pattern; sailors use the pattern to tell where they are. What is its main idea?
  • A.Lighthouses keep ships safe and help them find their way.
  • B.Lights can flash.
  • C.Rocks are dangerous.

LessonPrint · RI.4.2 · Set 21 · free to copy for classroom use

Answer key — Main Idea and Its Support

Set 21. Prints on its own sheet.

  1. 1.Beavers change the places where they live.
  2. 2.Bees are important for growing food.
  3. 3.The railways led to one time for the whole country.
  4. 4.Earthworms help keep soil healthy.
  5. 5.Volcanoes behave in different ways.
  6. 6.Roman roads were built to last.
  7. 7.Coral reefs are home to a great deal of sea life.
  8. 8.Lighthouses keep ships safe and help them find their way.

More practice for RI.4.2

State the main idea, show the details behind it, and summarize.

Teaching this next? The Main Idea and a Summary is the 40-minute plan for it, with the misconceptions to expect.

All Grade 4 worksheets

Last reviewed 2026-09-05. Aligned to RI.4.2 of the Common Core State Standards for English Language Arts.